> There will always be sidle-lobes.
Right, and anybody who knows enough to ask you about sidelobes likely also knows enough to know that too.
That's why, if you reply that "there are no sidelobes" you're only harming your own credibility.
A good reply is something like "there are sidelobes, but they peak at -{believable number} dB and are contained to within {small area}. We believe this is more than sufficient to address sidelobe concerns because of {standards}".
That's a reply that earns trust.